Design recommendations for reinforced concrete cylindrical storage structures for aqueous materials

1987 ◽  
Vol 14 (4) ◽  
pp. 542-549
Author(s):  
J. C. Jofriet ◽  
R. Green ◽  
T. I. Campbell
Keyword(s):  
Reinforced Concrete ◽  
Tensile Stress ◽  
Limit State ◽  
Water Storage ◽  
Lateral Wall ◽  
Temperature Gradients ◽  
Design Criteria ◽  
Storage Reservoirs ◽  
Storage Structures ◽  
State Criterion

The design of cylindrical non-prestressed concrete storage structures in Ontario does not appear governed by any standard or building code. Many aboveground water storage reservoirs in Ontario have deteriorated badly in a relatively short period of use. Many farm silos suffer from problems similar to those of the water storage reservoirs. This paper is concerned with the selection of the wall thickness and the hoop reinforcement for cylindrical storage tanks and silos for liquids or wet materials where tensile cracking of the concrete is to be limited.Three design criteria are presented. The first limits the circumferential tensile stress in the concrete from lateral wall pressure, shrinkage, and temperature gradients in the wall. The second is concerned with the tension in the hoop reinforcement and guards against collapse. The third limits the crack widths of the cracked concrete section. The most important design loads are discussed. Maximum values for hoop tension are provided for liquid pressures. A design temperature gradient of 15 °C is recommended for design in southern Ontario. As well, appropriate values of shrinkage tensile stress are suggested. The collapse limit state criterion must be evaluated for the hoop steel stresses due to the lateral wall loads. The limit state criterion related to the hoop tensile stress in the concrete must be investigated for all possible load combinations of lateral wall load, shrinkage, and temperature gradients. Reasonable load combination factors have been recommended. Recommendations on the tensile strength of concrete and on appropriate strength factors have been made. Key words: cylindrical tank, design criteria, hoop stresses, reinforced concrete, silo, standpipe, storage of liquids, storage of saturated bulk materials.

scholarly journals Reinforced concrete structures strengthened with CFRP (ACI x FIB) - Recommendations for bending design criteria

2022 ◽  
Vol 15 (2) ◽  
Author(s):  
Igor Del Gaudio Orlando ◽  
Túlio Nogueira Bittencourt ◽  
Leila Cristina Meneghetti
Keyword(s):  
Reinforced Concrete ◽  
Limit State ◽  
Concrete Structures ◽  
Experimental Tests ◽  
Fiber Reinforced Polymers ◽  
Design Criteria ◽  
Ultimate Limit State ◽  
Reinforced Concrete Structures ◽  
Carbon Fiber Reinforced Polymers ◽  
Model Code

abstract: This work deals with the evaluation of the design criteria and security check (Ultimate Limit State - ULS) of the American (ACI-440.2R, 2017) and European (FIB Model Code, 2010) standards of reinforced concrete structures strengthened with Carbon Fiber Reinforced Polymers (CFRP), by the technique of Externally Bonded Reinforcement (EBR). It is intended to evaluate if, for a given database of 64 experimental tests of beams and slabs, the obtained results respect the safety conditions according to the mentioned standards, to increase the efficiency of this reinforcement technique and to lead to the establishment of regulatory design criteria in Brazil. Results show a conservative match among experimental and theoretical values calculated according to the two guidelines and it is concluded that a future regulation in Brazil on this subject should be based on the FIB Model Code.

Combined Reinforced Concrete Columns Strengthening with Steel Clipping and Concrete Surfacing

2021 ◽  
pp. 11-22
Author(s):  
Ю. Г. Москалькова ◽  
С. В. Данилов ◽  
В. А. Ржевуцкая
Keyword(s):  
Reinforced Concrete ◽  
Load Transfer ◽  
Limit State ◽  
Concrete Columns ◽  
Ultimate Limit State ◽  
Concrete Core ◽  
Reinforced Concrete Columns ◽  
Entire Height ◽  
Complex Structural ◽  
Ultimate Limit

Постановка задачи. Исследуется метод усиления железобетонных колонн устройством стальной обоймы с обетонированием, который позволяет восстанавливать эксплуатационные показатели колонн, имеющих значительные дефекты и повреждения. Предпосылкой настоящих исследований явилось предположение о том, что усиление стальной обоймой с обетонированием является эффективным способом повышения несущей способности железобетонных колонн, причем вариант приложения нагрузки - только на бетонное ядро или ко всему сечению - существенно на эффективность усиления не влияет. В связи с этим целью исследования является определение необходимости устройства стального оголовка и включения в работу ветвей стальной обоймы при условии обетонирования стержня колонны по всей высоте. Результаты и выводы. Рациональным признан способ передачи нагрузки только на бетонное ядро усиленных колонн, поскольку устройство оголовка стальной обоймы требует применения сложных конструктивно-технологических решений, но при этом дополнительно увеличивает несущую способность незначительно (согласно проведенным исследованиям менее чем на 10 %). Ввиду отсутствия необходимости устройства конструкций стального оголовка снижаются трудоемкость и сроки производства работ по усилению колонн. Statement of the problem. The method of strengthening reinforced concrete columns with a steel clipping and the concrete surfacing is investigated. This method allows one to repair the columns with significant defects and damage. The prerequisite for this study was the assumption of strengthening with a steel clipping and the concrete surfacing is an effective way to increase the ultimate limit state of reinforced concrete columns, furthermore, the option of applying the load (only to the concrete core or to the entire section) does not significantly affect the strengthening effectiveness. In this regard, the purpose of the investigation was to identify the need to include the steel jacketing in the work, on the condition the column is coated with concrete along with the entire height. Results and conclusions. The load transfer method only to the concrete core of the strengthened columns is recognized as rational since the device of the steel clipping head requires the use of complex structural and technological solutions, but at the same time additionally increases the ultimate limit state insignificantly (according to the studies by less than 10 %). Due to the absence of the need to establish structures of the steel jacketing head, the labor intensiveness and terms of work production on strengthening the columns are reduced.

scholarly journals Behavioural Study of Shear Wall with Correlational to Bracing under Seismic Loading

2018 ◽  
Vol 65 ◽  
pp. 08008
Author(s):  
Syed Muhammad Bilal Haider ◽  
Zafarullah Nizamani ◽  
Chun Chieh Yip
Keyword(s):  
Reinforced Concrete ◽  
Lateral Displacement ◽  
Limit State ◽  
Shear Wall ◽  
Design Tool ◽  
Base Shear ◽  
Building Model ◽  
High Rise ◽  
Finite Element Software ◽  
Seismic Vibrations

The reinforced concrete structures, not designed for seismic conditions, amid the past earthquakes have shown us the significance of assessment of the seismic limit state of the current structures. During seismic vibrations, every structure encountered seismic loads. Seismic vibrations in high rise building structure subjects horizontal and torsional deflections which consequently develop extensive reactions in the buildings. Subsequently, horizontal stiffness can produce firmness in the high rise structures and it resists all the horizontal and torsional movements of the building. Therefore, bracing and shear wall are the mainstream strategies for reinforcing the structures against their poor seismic behaviours. It is seen before that shear wall gives higher horizontal firmness to the structure when coupled with bracing however it will be another finding that in building model, which location is most suitable for shear wall and bracing to get better horizontal stability. In this study, a 15 story residential reinforced concrete building is assessed and analyzed using building code ACI 318-14 for bracing and shear wall placed at several different locations of the building model. The technique used for analysis is Equivalent Static Method by utilizing a design tool, finite element software named ETABS. The significant parameters examined are lateral displacement, base shear, story drift, and overturning moment.

scholarly journals Water storage reservoirs and their role in the development, utilization and protection of catchment

Spatium ◽  
2011 ◽  
pp. 9-15
Author(s):  
Branislav Djordjevic ◽  
Tina Dasic
Keyword(s):  
Water Management ◽  
Sustainable Development ◽  
Development Strategy ◽  
Water Storage ◽  
The Sustainable Development ◽  
Storage Reservoirs ◽  
Development Plans ◽  
The Creation ◽  
Negative Impacts ◽  
Hydrological Regimes

Reasons why water storage reservoirs are necessary in accordance with the sustainable development strategy are described in the paper. The main positive and negative impacts of reservoirs on the environment are analyzed. The most important are: the improvement of hydrological regimes (decreasing maximal and increasing minimal flows), the creation of optimal water management, utilization and protection of water, and the creation of better conditions for river and coastal ecosystems. Negative impacts and measures for its mitigation or elimination are also analyzed. The conclusion is that water storage reservoirs can be harmoniously incorporated into the environment. Serbia has a limited number of locations suitable for the construction of reservoirs, therefore it is necessary to retain these areas for storage in regional development plans and other legal acts.

scholarly journals Strength criterion for a plane stress reinforced concrete element under a special action

Vestnik MGSU ◽  
2020 ◽  
pp. 1513-1522
Author(s):  
Natalia V. Fedorova ◽  
Vu Ngoc Tuyen ◽  
Igor A. Yakovenko
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Concrete Strength ◽  
Limit State ◽  
Strength Criterion ◽  
Structural Systems ◽  
Variable Loading ◽  
Concrete Element ◽  
Theory Of Plasticity ◽  
Concrete Elements

Introduction. Problem solving focused on the protection of buildings and structures from progressive collapse and minimization of resources, needed for this purpose, is becoming increasingly important. In many countries, including Russia, this type of protection is incorporated into national regulatory documents, and, therefore, any research, aimed at developing effective ways to protect structural systems from progressive collapse under special actions, is particularly relevant. In this regard, the present article aims to formulate effective strength criteria for such anisotropic materials as reinforced concrete to analyze plane stressed reinforced concrete structures exposed to sudden structural transformations caused by the removal of one of bearing elements. Materials and methods. To solve this problem, a variant of the generalized theory of plasticity of concrete and reinforced concrete, developed by G.A. Geniev, is proposed for application to the case of variable loading of a plane stressed reinforced concrete element. The acceptability of generalization of the strength criterion, pursuant to the theory of plasticity of concrete and reinforced concrete under static loading, and the applicability of this criterion to variable static-dynamic loading of reinforced concrete are used as the main hypothesis. An algorithm of an approximate method is presented as a solution to this problem; it allows to analyze the considered stress-strain state of plane stressed reinforced concrete elements. Results. The numerical analysis of the obtained solution, compared with the results of the experimental studies, was used to evaluate the designed strength criterion for reinforced concrete elements located in the area where the column is connected to the girder of a monolithic reinforced concrete frame in case of a sudden restructuring of a structural system. It is found out that the qualitative nature of the destruction pattern of the area under research, obtained in experiments, corresponds to the destruction pattern, identified by virtue of the analysis performed using the proposed criterion. Conclusions. The variant of the reinforced concrete strength criterion designated for the variable loading of a plane stressed reinforced concrete element and an algorithm for its implementation, based on the theory of plasticity of concrete and reinforced concrete developed by G.A. Geniev, is applicable to the analysis of a special limit state of reinforced concrete elements of structural systems of frames of buildings and structures.

Analytical Solutions for Flexural Stress of One-way UHPC-NC Hybrid Slab

2019 ◽  
Author(s):  
Zhao Liu ◽  
Wei D. Zhuo ◽  
Si Q. Yuan
Keyword(s):  
Tensile Stress ◽  
Layer Thickness ◽  
Analytical Solutions ◽  
High Performance Concrete ◽  
Limit State ◽  
Neutral Axis ◽  
Thickness Ratio ◽  
Slab Thickness ◽  
Flexural Stress ◽  
Axis Position

<p>Ultra‐high performance concrete (UHPC) is an advanced construction material that affords opportunities to innovate the structures made of conventional concrete (NC). The one‐way UHPC‐NC hybrid slab, designed to have the UHPC layer in tension and the NC layer in compression, can be an optimal use of UHPC for bridge deck. The analytical solutions for normal stress are essential under service limit state, but they cannot be found in the literature by now. Based on the elastic theory, analytical formulas for the neutral axis position and flexural stress are derived. The lowest neutral axis position is attained when the UHPC layer thickness ratio (UHPC layer thickness / hybrid slab thickness) approximates 0.4. The criteria to judge the position of neutral axis within UHPC or NC region are analytically established. To find out the ideal scenario to reach the allowable compressive stress in NC and allowable tensile stress in UHPC simultaneously, an inequality constraint with the elastic modulus ratio is proposed. Considering the UHPC tensile stress limitation and flexural moment capacity of the hybrid slab, the rational thickness ratio of UHPC layer of 0.4 is suggested, which can achieve better economy and efficiency of the hybrid slab.</p>

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